A system for recovering heat energy included in compressed gas that has been discharged from a compressor has been recently proposed. For example, Patent Document 1 discloses an energy recovery system of a compression device including: a compressor; an evaporator for conducting heat exchange between compressed gas that has been discharged from the compressor and a liquid-phase working medium; a cooler for cooling the gas that has flowed out from the evaporator; a turbine in which the gas-phase working medium that has flowed out from the evaporator flows; an AC generator connected to the turbine; a condenser for condensing the working medium that has flowed out from the turbine; and a circulating pump for pumping the liquid-phase working medium that has flowed out from the condenser, to the evaporator. In this system, energy included in the compressed gas is recovered in the evaporator and by using the energy, electric power generation is performed in the AC generator.
In the system disclosed in the foregoing Patent Document 1, a pressure loss is desired to be reduced as much as possible so that pressure of the compressed gas discharged from the compressor may be a desired value. However, since the evaporator is provided, a pressure loss of the compressed gas in a flow passage may increase. Therefore, in order to maintain the pressure of the compressed gas, power of the compressor needs to be increased. As a result, heat energy, which is to be effectively recovered in the energy recovery system may decrease. Note that nothing has been mentioned in Patent Document 1 about a means for reducing a pressure loss.